This invention relates to systems and methods of binding sheets by activating a microencapsulated binding agent.
Today, a variety of different bookbinding systems can deliver professionally bound documents, including books, manuals, publications, annual reports, newsletters, business plans, and brochures. A bookbinding system generally may be classified as a commercial (or trade) bookbinding system that is designed for in-line manufacturing of high quality volume runs or an in-house (or office) bookbinding system designed for short xe2x80x9con-demandxe2x80x9d runs. Commercial bookbinding systems generally provide a wide variety of binding capabilities, but require large production runs (e.g., on the order of thousands of bindings) to offset the set-up cost of each production run and to support the necessary investment in expensive in-line production equipment. Office bookbinding systems, on the other hand, generally involve manual intervention and provide relatively few binding capabilities, but are significantly less expensive to set up and operate than commercial bookbinding systems, even for short on-demand production runs of only a few books.
In general, a bookbinding system collects a plurality of sheets (or pages) into a text body (or book block) that includes a spine and two side hinge areas. The bookbinding system applies an adhesive to the text body spine to bind the sheets together. A cover may be attached to the bound text body by applying an adhesive to the side hinge areas or the spine of the text body, or both. The cover of a typical commercial soft cover book generally is attached to the text spine. The covers of hardcover books and some soft cover xe2x80x9clay flatxe2x80x9d books, on the other hand, typically are not attached to the text body spines (i.e., the spines are xe2x80x9cfloatingxe2x80x9d).
Many different systems have been proposed for applying adhesive to a text body spine to bind the text body sheets together.
For example, U.S. Pat. No. 5,346,350 discloses an apparatus for binding sheets that includes an aligning plate that aligns the sheets edges at the spine edge, and two clamping plates that hold the sheets during binding. A heating platen heats and melts a backless solid hot melt adhesive that is placed along the sheet edges. The hot melt adhesive binds the sheets together at the spinal area. The hot melt adhesive also may be used to attach a preformed book cover to the text body spine.
International Patent Publication No. WO 99/38707 discloses a paperback bookbinding scheme in which a cover with an adhesive strip disposed along a spine area is forced between a pair of pressing rollers to form a pocket, and a text body is inserted into the pocket with the text body spine in contact with the adhesive strip. The pressing rollers are moved forcibly toward one another to compress the cover firmly against the front and back sides of the text body and to compress the text body sheets together tightly in the area adjacent to the spine. A sonic tool transmits sonic energy to the cover to activate the adhesive strip and, thereby, bind the text body sheets and the cover into a perfectly bound book.
U.S. Pat. No. 4,911,475 discloses a bookbinding construction in which sheets are bound together into a book block by two or more spaced-apart transverse segments of adhesive. The front section of a cover is attached to the first page of the book block and the back section of the cover is secured to the last page of the book block. Upon opening the book or turning a page, glue-free portions of the spine edge of the open page flex or bow outward over the facing page in a wedging manner or interfering fit. According to the ""475 patent, this wedging action against the opposite page resists the tendency of the book to spring closed and forces the pages of the book to lie flat.
U.S. Pat. No. 5,271,794 discloses an adhesive applicator that is configured to spread coat an adhesive onto the spine and side edges of a text body to bind the text body sheets and a cover into a perfectly bound book with an attached spine. The adhesive applicator includes a book spine coating nozzle with adjustable side sealing jaws for adjusting the nozzle width for different book thicknesses and separate side glue outlets for depositing glue on the book sides. Glue flow control valves are disposed between the spine coating nozzle and the side glue outlets so the glue deposited on the book sides may be selectively and independently cut off or controlled.
Adhesive systems that use activatable microcapsules also have been proposed.
For example, U.S. Pat. No. 4,940,852 discloses a pressure sensitive adhesive system that includes a curable adhesive mixed with a plurality of rupturable microcapsules filled with a curing agent.
U.S. Pat. No. 5,532,293 discloses an adhesive system for tamper-evident envelopes. The adhesive system includes a dried cohesive latex containing gelatin and a plurality of solvent-filled microcapsules. Upon application of pressure, the microcapsules are ruptured, whereby the solvent is released to dissolve the cohesive material and form a bond.
U.S. Pat. No. 6,084,010 discloses a hot melt adhesive composition that includes at least one ingredient present in an encapsulated form. The encapsulated ingredient may be any known hot melt adhesive formulation ingredient as well as any hot melt adhesive additive such as antioxidants and fragrances for which there is a desirable change in adhesive properties by isolating such ingredient for a duration of time. The encapsulated ingredient is released from the shell by means of pressure, temperature, diffusion, pH, light, radiation, ultrasound, and combinations thereof.
Still other adhesive systems that include activatable microcapsules have been proposed.
The invention features novel systems and methods of binding sheets by activating a microencapsulated binding agent.
In one aspect of the invention, each sheet to be bound has an exposed frontside binding surface region near a spine edge. A frontside adhesive system is disposed over the frontside binding surface region and comprises a binding agent that is encapsulated in a plurality of microcapsules. The adhesive system is non-tacky to enable the sheets to be stacked and individually processed until the binding agent is released from the microcapsules.
Embodiments in accordance with this aspect of the invention may include one or more of the following features.
In some embodiments, each sheet has an exposed backside binding surface region near the spine edge and a backside adhesive system disposed over the backside binding surface region. The frontside adhesive system may have the same or different composition as the backside adhesive system. In one embodiment, the frontside adhesive system comprises a main component of a two-part epoxy resin system and the backside adhesive system comprises a curing agent of the two-part epoxy resin system. The frontside binding surface region and the backside binding surface region may be located on the same side or on opposite sides of each sheet. In embodiments with frontside and backside binding surfaces located on the same sheet side, each sheet may be scored along a fold line disposed between the frontside binding surface region and the backside binding surface region.
As used herein, the terms xe2x80x9cfrontsidexe2x80x9d and xe2x80x9cbacksidexe2x80x9d are intended merely to distinguish one side of a sheet from the opposite side. These terms are not intended to indicate any particular absolute sheet orientation or position.
The binding agent may comprise an adhesive composition. Alternatively, the frontside adhesive system may comprise a non-tacky adhesive and the binding agent may comprise an adhesive activator. In some embodiments, the frontside adhesive system comprises first and second binding agents each encapsulated in a respective plurality of microcapsules, wherein the first binding agent comprises a main component of a two-part epoxy resin system and the second binding agent comprises a curing component of the two-part epoxy resin system.
The binding agent may be released from the microcapsules by exposure to radiation.
In some embodiments, the frontside adhesive system has a machine-readable characteristic from which information may be extracted automatically. The machine-readable characteristic may be indicative of sheet type or adhesive type, or both.
In another aspect, the invention features a bookbinding system that includes a sheet collector that is configured to form a text body from a plurality of the above-described sheets, and an adhesive activator that is configured to activate the adhesive system of each sheet to form a bound text body.
Embodiments in accordance with this aspect of the invention may include one or more of the following features.
The adhesive activator may be configured to activate the adhesive system of each sheet of the text body by applying radiation to the encapsulated binding agent. For example, the adhesive activator may include a microwave cavity that is configured to receive a spine end of the text body and apply microwave energy to the encapsulated binding agent of each sheet.
The bookbinding system also may include a sensor that is configured to extract information from a machine-readable characteristic of the adhesive system. For example, the sensor may be configured to interrogate a radiation response characteristic of the adhesive system.
The invention also features a method of binding the above-described sheets into a bound text body by activating the adhesive system of each sheet.
Other features and advantages of the invention will become apparent from the following description, including the drawings and the claims.